There have been known that the following compounds (1), (2), (3), (4), (5), (6) and (7) are useful as an anxiolytic drug and a psychotropic drug.
(1) JP-A-56-43283 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"):
It has been known that a .beta.-carboline-3-carboxylic acid derivative of the following general formula: ##STR3## is useful as a neuroleptic having an antiaggresive action.
Also, it has been known that the following tetrahydropyridine derivatives and pyridine derivatives (2), (3), (4), (5), (6) and (7) have psychotropic effects.
(2) JP-A-61-236779:
A compound of the following formula: ##STR4## (3) JP-A-63-096188:
A compound of the following formula: ##STR5## (4) JP-A-63-096189:
A compound of the following formula: ##STR6## (5) JP-A-1-100172:
A compound of the following formula: ##STR7## (6) JP-A-2-149583:
A compound of the following formula: ##STR8## (7) WO89-12447:
A compound of the following formula: ##STR9## Further, there have been made many studies on the synthesis of 1,2,3,4-tetrahydrobenzo[b]thieno[2,3-c]pyridine or derivatives thereof as reported, for example, in Gerhard Wolf and Felix Zymalkowski, Arch. Pharm., 279, 309 (1976)] and biochemical studies on the effects of these compounds on the brain, as reported, for example, in Brandley V. Clineschmidt, Duane R. Reiss, Douglas J. Pettibone and Janet L. Robinson, J. Pharmacol. Exp. Ther., 696-708, 235 (3) (1985). However no such a tetrahydropyridine derivative having substituents on three rings as the one of the present invention has been known so far.
It is an object of the present invention to provide a novel tetrahydropyridine derivative having substituents on three rings which is useful as a drug having antianxiety and learning-improvement effects.